Fundamentals of Plant Physiology is a comprehensive and student-oriented textbook designed strictly as per the ICAR VI Deans' Committee syllabus for undergraduate courses in agriculture and allied sciences. The book systematically presents the fundamental concepts of plant physiology, starting from basic principles to advanced physiological processes that govern plant growth, development, and productivity. Each chapter is organized in a logical and coherent manner, integrating classical knowledge with recent developments in the field. Emphasis has been laid on clarity of concepts, scientific accuracy, and practical relevance, making the book highly useful for understanding the physiological basis of crop performance under diverse environmental conditions. The book is primarily intended for B.Sc. (Agriculture), B.Sc. (Horticulture), and other undergraduate students of agricultural universities across India. Extension workers, agronomists, and professionals involved in crop production and management will also find this book helpful in strengthening their conceptual understanding of plant processes and their applications in improving crop productivity and sustainability.